1. Field of the Invention
The present invention generally relates to an audio broadcasting system, more particularly to an audio broadcasting system and method for broadcasting audio signals in a vehicle.
2. Description of the Prior Art
Recently, the electronic products are developed to be light, thin, short and small. The popular pen driver is one of the examples. Since it has small volume and large memory capacity, it has already replaced the traditional floppy disk. Via combining other functions, the pen driver can also be used to record sounds, receive broadcasting, play MP3 music files and so on.
Car audio systems usually comprise a radio and a CD or cassette player. Plainly an MP3 music file cannot be played through such systems directly, and it has been proposed to provide a connection lead for audio output of the MP3 player. Such leads are not practicable for some car audio systems, but if suitable usually comprise a power lead and an audio signal lead, each connecting to different parts of the car dashboard. These leads are long in order to be suitable for all kinds of vehicle, and can be considered dangerous if they obstruct the vehicle controls. Generally speaking, such connection leads are unreliable and very undesirable.
An adaptor powered by the cigarette lighter in a car can play MP3 or WAV music files stored in the adaptor through the car audio system. That is, the adaptor converts the MP3 or WAV music files to particular FM signals and transmits the FM signals wirelessly to the car radio. The car audio system then broadcasts the received FM signals. In this way, no more undesirable and unreliable leads are needed. After finding out a particular frequency channel without noise or signal interference, users can tune the adaptor to transmit the FM signals corresponding to the particular frequency channel; the FM signals can be broadcasted clearly. The adaptor can be connected to a music (including MP3 or WAV or other audio formats) player for converting MP3 or WAV music files stored in the music player to particular FM signals. Thus, the car audio system can broadcast music files stored in the MP3 player.
However, the adaptor comprises a LCD for displaying FM channels, a plurality buttons for tuning FM channels and a memory for storing music files, therefore, the cost of the adaptor aforementioned is very expensive.
For solving the problem above, some music players are designed with a built-in FM processor for converting MP3 or WAV music files stored in the music player to particular FM signals and transmitting the particular FM signals wirelessly. Therefore, the car broadcasting system plays the particular FM signals transmitted from the music player directly without processing through the adaptor. Although the adaptor is no longer needed, however, the built-in FM processor increases the cost of the music players.
It is desirable, therefore, to provide a low cost adaptor to allow for converting the MP3 or WAV music files to particular FM signals and transmitting the FM signals wirelessly to the car radio.